Michael Beirne
Mrs. Parks
Honors Biology
11 April 2014
DNA Fingerprinting and PCR
DNA fingerprinting, or sometimes known as DNA typing, is isolating and developing images of sequences of DNA to evaluate the DNA in an individual’s cells. DNA fingerprinting today is used for many different things in many different areas of science. In forensic science, DNA typing can determine which person did which crime by using blood or skin left at a crime scene. In medical science, patients can find out who their siblings, parents, or children are by using DNA fingerprinting (webmd).
It was in 1984 when Alec Jeffreys, a British geneticist, discovered that specific sequences of DNA did not add to the function of a gene but were still constant throughout it. (Britannica). Jeffreys called these minisatellites and determined that each individual organism had a unique arrangement of minisatellites (Britannica). In the early uses of DNA fingerprinting, it was only used for identifying genetic diseases and disorders but people quickly realized that it could be used in many different areas of science (hubpages). Years after the discovery of DNA fingerprinting, it had been used to solve the first immigration case, the first paternity case, and even helped identify the first identical twins (le.ac.uk). The first methods of DNA fingerprinting were accurate, but you would have had needed to acquire a large amount of DNA. Over time, the advancement of science has led to major advances that formed the basis of DNA profiling techniques. These newer methods are still used today and allow scientist to use skin, blood, semen, and hair to gather DNA (le.ac.uk). In 1988 DNA fingerprinting was used for the first time in a criminal investigation. Timothy Spe...
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...eloped research that displays that as many as four percent of DNA matches in forensic laboratories have been in fault (legal-dictionary).
Gene mapping is currently being used to identify genes that can put people at risk for illness and to help the development of new medicines. Scientists hope to use gene mapping to lead to advancement in medicines, the treatment to disease, and its aid in disease prevention. Genetic mapping was the initial step in the Human Genome Project (human genome project). The Human Genome Project identified thousands of DNA sequences and located important standards they called landmarks. Scientist use these landmarks to tell them where each fragment of DNA came from. These maps would be used to locate sick genes, diseases, or abnormal genes (genome.gov). Two types of genetic maps are constructed: linkage mapping and physical mapping.
It helps medics to find a direct genetic cause of the patient’s condition and target it with pharmaceutical or other therapies. The technology is used for the identification of DNA sequences that increase risks of current diseases and disorders; with this information carriers can start to make efforts to prevent them before the development of the problem. The video mentioned 200 actionable genes, structures that have direct links with a specific condition. Knowing about their presence, people have a chance to bring in preventive measures like taking anticoagulants in the case of identification of a thrombogenic gene. The technology led to the significant improvement of diagnostics and personalized treatments. It helped to find a rare, life-threatening mutation in case of Beery twins and assign a drug to a girl (Alexis) that returned her to a normal life. In the case of cancer genome sequencing led to the development of genetic drags, which target essential tumor genes and make malign structures to shrink. The video mentioned a product that works with the BRАF protein that induces cells to uncontrolled division; the drug led to the remission in the patient with metastasizing melanoma. Such treatment was effective in the case of cystic fibrosis. In the case of the breast cancer the technology helps to evaluate the aggressiveness of the condition and make a personalized decision about chemotherapy. The video also mentioned the pre-implantation genetic diagnosis – an early-staged technology that prevents the development of inherited disorders in
DNA is the blueprint of life. It stores our genetic information which is what is in charge of how our physical appearance will look like. 99.9% of human DNA is the same in every person yet the remaining .1% is what distinguishes each person (Noble Prize). This small percentage is enough to make each person different and it makes identifying people a lot easier when its necessary. DNA not only serves to test relationships between people it also helps in criminal cases. DNA testing in criminal cases has not been around for many years if fact it was not until the early 1990s when the use of DNA testing for criminal cases was approved and made available. By comparing the DNA of a suspect and that found in the crime scene a person can either be convicted of a crime or they can be exonerated. This method of testing gained more publicity in the 1984 case of Kirk Noble Bloodsworth a man who had been convicted of the rape and first degree murder of a nine year old girl in Maryland. His case was a milestone in the criminal justice system since it involved the use of new technology and it also raised the question of how many people had been wrongly incarcerated for a crime they did not commit.
PCR or polymerase chain reaction is not a DNA typing technique, but a variety of different DNA tests (Riley). PCR duplicates and increases the quantity of a DNA strand which is beneficial to forensic scientists who are faced with little quantity of materials (Saferstein 394). The introduction of PCR-based testing in DNA analysis required scientists to switch to smaller targets that had the same repetitive variation (Jones). This is how short tandem repeat, the newest method of DNA typing,
Nowadays, DNA is a crucial component of a crime scene investigation, used to both to identify perpetrators from crime scenes and to determine a suspect’s guilt or innocence (Butler, 2005). The method of constructing a distinctive “fingerprint” from an individual’s DNA was first described by Alec Jeffreys in 1985. He discovered regions of repetitions of nucleotides inherent in DNA strands that differed from person to person (now known as variable number of tandem repeats, or VNTRs), and developed a technique to adjust the length variation into a definitive identity marker (Butler, 2005). Since then, DNA fingerprinting has been refined to be an indispensible source of evidence, expanded into multiple methods befitting different types of DNA samples. One of the more controversial practices of DNA forensics is familial DNA searching, which takes partial, rather than exact, matches between crime scene DNA and DNA stored in a public database as possible leads for further examination and information about the suspect. Using familial DNA searching for investigative purposes is a reliable and advantageous method to convict criminals.
Saltus, Richard. "DNA Fingerprinting: Its A Chance Of Probabilties." The Boston Globe 22 August 1994: 25.
States. The FBI performs testing for free to all police agencies to help keep costs down
DNA in forensic science has been around for a long time. DNA has had help in solving almost every crime committed. There have been a lot of crimes where people are raped or murdered and the person who did it runs free. Scientists can collect the littlest item they see at the scene, such as a cigarette butt or coffee cup and check it for DNA. People have spent years in jail for a crime they didn’t commit till DNA testing came into effect. People are getting out of jail after 20 years for a crime they didn’t commit, cause of the DNA testing. DNA has helped medical researchers develop vaccines for disease causing microbe. DNA has become a standard tool of forensics in many murders and rapes.
DNA, or deoxyribonucleic exists in all living organisms, is self-replicating and gives a person their unique characteristics. No two people have the same matching DNA. There are many different forms of DNA that are tested for situations such as criminal. Bodily fluids, hair follicles and bone tissues are some of the most common types of DNA that is tested in crime labs today. Although the discovery of DNA dates back to 1866 when Gregor Mendel proved the inheritance of factors in pea plants, DNA testing is relatively new and have been the prime factor when solving crimes in general. In 1966, scientists discovered a genetic code that made it possible to predict characteristics by studying DNA. This lead to genetic engineering and genetic counseling. In 1980, Organ was the first to have a conviction based off DNA fingerprinting and DNA testing in forensics cases became famous in 1995 during the O.J. Simpson trial (SMC History , 2011).
Palermo explains the “…means of impeding the presentation of sloppy scientific evidence is found Federal Rule of Evidence 403 that gives judges the discretion to admit or to exclude from trial evidence, including scientific, deemed to prejudicial, confusing, or misleading to jurors” (2006). The article then explains that the technical terms used in the trial court while presenting the DNA analyses, is many times too complex for the individuals sitting on the jury. Ultimately, these same jurors are still inclined to reject or accept the facts presented even if they don’t understand the information presented. Palermo also commented on the necessity for better training on the individuals that come in close contact with the collection of DNA evidence, because it’s imperative, as is the training of DNA analysts and others involved with the handling of evidence. The collection of evidence plays a viable role in the process of DNA examination because if evidence isn’t collected properly the evidence could easily be contaminated with other elements from the crime scene.
The genetic technology revolution has proved to be both a blessing and a blight. The Human Genome Project is aimed at mapping and sequencing the entire human genome. DNA chips are loaded with information about human genes. The chip reveals specific information about the individuals’ health and genetic makeup (Richmond & Germov 2009).The technology has been described as a milestone by many in that it facilitates research, screening, and treatment of genetic conditions. However, there have been fears that the technology permits a reduction in privacy when the information is disclosed. Many argue that genetic information can also be used unfairly to discriminate against or stigmatize individuals (Willis 2009).
Deoxyribonucleic acid (DNA) is an acclaimed extraordinary discovery that has contributed great benefits in several fields throughout the world. DNA evidence is accounted for in the majority of cases presented in the criminal justice system. It is known as our very own unique genetic fingerprint; “a chromosome molecule which carries genetic coding unique to each person with the only exception of identical twins (that is why it is also called 'DNA fingerprinting ')” (Duhaime, n.d.). DNA is found in the nuclei of cells of nearly all living things.
DNA is a vital tool in forensic medicine, when it comes to tracking down that killer or finding that liar in the courtroom. However, DNA fingerprinting for example is also used to identify what a person did based off of their remains. “The U.S. military takes blood and saliva samples from every recruit so it can identify victims of mass disasters such as airplane crashes.” (Marieb, 2009, p.459). After the 9/11 attacks,
Fingerprint usage dates back to the 1800s. Sir William Herschel used the prints as signatures on civil contracts, before they were found useful towards crimes (History of Fingerprints Timeline, 2012). A British surgeon, Dr. Henry Faulds, wrote about using fingerprints for personal identification. He first looked at prints on clay pottery and studied the ridges and patterns that they had made in the clay. In 1891, Juan Vucetich suggested to start fingerprinting criminals to keep the prints on record. The following year, Vucetich identified a print from a woman who killed her two sons. Investigators found her print and were able to correctly match her identity. Charles Darwin’s cousin, Sir Francis Galton, wrote and published the first book about fingerprints. He wrote about how every individual has a unique print by the certain traits of each fingerprint (History of Fingerprints, 2012). The popularity of fingerprints grew greatly in the United States in the early 1900s. Police departments and the FBI began to use the...
Deoxyribonucleic acid is what carries the hereditary and genetic code of humans. Each human has chromosomes that carry their DNA, 23 received from the mother and 23 from the father totaling 46. Most DNA is not different from other individuals, only 0.10% of each person’s DNA is unique. Law enforcement is able to track down suspected criminals by analyzing this small percentage. As stated in DNA biometrics, “The chance of two individuals sharing the same DNA profile is less than one in a hundred billion” (DNA Biometrics). With this being said, once law enforcement has obtained an individual’s DNA at a crime scene, they are able to run it through their labs and databases to find out which individual they are looking for. Many different items from your body can be used to obtain your DNA such as blood, hair, saliva, tissue, and semen (DNA Biometrics).
Modern technology allows DNA to be extracted from even the tiniest biological sample, which may be a few droplets of blood or a hair follicle. Moreover, once the samples are compiled, they can be analysed to create DNA profiles that can aid in identifying a specific person. If all tested profiles match, the samples come from the same person. Conversely, if they do not match, that means the samples come from different